Deploying Jobs on Google Kubernetes Engine
In GKE, a Job is a controller object that represents a finite task. Jobs manage a task as it runs to completion, rather than managing an ongoing desired state such as maintaining the total number of running Pods.
CronJobs perform finite, time-related tasks that run once or repeatedly at a time that you specify using Job objects to complete their tasks.
- Define, deploy and clean up a GKE Job
- Define, deploy and clean up a GKE CronJob
Define and deploy a Job manifest
In this task, you create a Job, inspect its status, and then remove it.
Welcome to Cloud Shell! Type "help" to get started.
Your Cloud Platform project in this session is set to qwiklabs-gcp-03-7569ff0296bd.
Use “gcloud config set project [PROJECT_ID]” to change to a different project.
student_02_c4beb0285b69@cloudshell:~ (qwiklabs-gcp-03-7569ff0296bd)$ export my_region=us-east1
export my_cluster=autopilot-cluster-1
student_02_c4beb0285b69@cloudshell:~ (qwiklabs-gcp-03-7569ff0296bd)$ source <(kubectl completion bash)
student_02_c4beb0285b69@cloudshell:~ (qwiklabs-gcp-03-7569ff0296bd)$ gcloud container clusters get-credentials $my_cluster --region $my_region
Fetching cluster endpoint and auth data.
kubeconfig entry generated for autopilot-cluster-1.
student_02_c4beb0285b69@cloudshell:~ (qwiklabs-gcp-03-7569ff0296bd)$ kubectl get nodes
NAME STATUS ROLES AGE VERSION
gk3-autopilot-cluster-1-nap-iw5ihjci-65ca1e83-9vk9 Ready <none> 74s v1.29.4-gke.1043002
student_02_c4beb0285b69@cloudshell:~ (qwiklabs-gcp-03-7569ff0296bd)$
Create and run a Job
Let’s create a sample Job that computes the value of Pi to 2,000 places and then prints the result.
- Create and open a file called
example-job.yaml
student_02_c4beb0285b69@cloudshell:~ (qwiklabs-gcp-03-7569ff0296bd)$ cat example-job.yaml
apiVersion: batch/v1
kind: Job
metadata:
# Unique key of the Job instance
name: example-job
spec:
template:
metadata:
name: example-job
spec:
containers:
- name: pi
image: perl:5.34
command: ["perl"]
args: ["-Mbignum=bpi", "-wle", "print bpi(2000)"]
# Do not restart containers after they exit
restartPolicy: Never
student_02_c4beb0285b69@cloudshell:~ (qwiklabs-gcp-03-7569ff0296bd)$
student_02_c4beb0285b69@cloudshell:~ (qwiklabs-gcp-03-7569ff0296bd)$ kubectl apply -f example-job.yaml
Warning: autopilot-default-resources-mutator:Autopilot updated Job default/example-job: defaulted unspecified 'cpu' resource for containers [pi] (see http://g.co/gke/autopilot-defaults).
job.batch/example-job created
student_02_c4beb0285b69@cloudshell:~ (qwiklabs-gcp-03-7569ff0296bd)$
student_02_c4beb0285b69@cloudshell:~ (qwiklabs-gcp-03-7569ff0296bd)$ kubectl describe job example-job
Name: example-job
Namespace: default
Selector: batch.kubernetes.io/controller-uid=b43189af-5981-466e-9837-e6f1e0772120
Labels: batch.kubernetes.io/controller-uid=b43189af-5981-466e-9837-e6f1e0772120
batch.kubernetes.io/job-name=example-job
controller-uid=b43189af-5981-466e-9837-e6f1e0772120
job-name=example-job
Annotations: autopilot.gke.io/resource-adjustment:
{"input":{"containers":[{"name":"pi"}]},"output":{"containers":[{"limits":{"cpu":"500m","ephemeral-storage":"1Gi","memory":"2Gi"},"request...
autopilot.gke.io/warden-version: 2.9.37
Parallelism: 1
Completions: 1
Completion Mode: NonIndexed
Start Time: Mon, 10 Jun 2024 01:17:28 +0000
Completed At: Mon, 10 Jun 2024 01:21:39 +0000
Duration: 4m11s
Pods Statuses: 0 Active (0 Ready) / 1 Succeeded / 0 Failed
Pod Template:
Labels: batch.kubernetes.io/controller-uid=b43189af-5981-466e-9837-e6f1e0772120
batch.kubernetes.io/job-name=example-job
controller-uid=b43189af-5981-466e-9837-e6f1e0772120
job-name=example-job
Containers:
pi:
Image: perl:5.34
Port: <none>
Host Port: <none>
Command:
perl
Args:
-Mbignum=bpi
-wle
print bpi(2000)
Limits:
cpu: 500m
ephemeral-storage: 1Gi
memory: 2Gi
Requests:
cpu: 500m
ephemeral-storage: 1Gi
memory: 2Gi
Environment: <none>
Mounts: <none>
Volumes: <none>
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal SuccessfulCreate 4m52s job-controller Created pod: example-job-zww22
Normal Completed 42s job-controller Job completed
student_02_c4beb0285b69@cloudshell:~ (qwiklabs-gcp-03-7569ff0296bd)$
student_02_c4beb0285b69@cloudshell:~ (qwiklabs-gcp-03-7569ff0296bd)$ kubectl get pods
NAME READY STATUS RESTARTS AGE
example-job-zww22 0/1 Completed 0 4m22s
student_02_c4beb0285b69@cloudshell:~ (qwiklabs-gcp-03-7569ff0296bd)$
Clean up and delete the Job
When a Job completes, the Job stops creating Pods. The Job API object is not removed when it completes, which allows you to view its status. Pods created by the Job are not deleted, but they are terminated. Retention of the Pods allows you to view their logs and interact with them.
student_02_c4beb0285b69@cloudshell:~ (qwiklabs-gcp-03-7569ff0296bd)$ kubectl get jobs
NAME COMPLETIONS DURATION AGE
example-job 1/1 4m11s 6m1s
student_02_c4beb0285b69@cloudshell:~ (qwiklabs-gcp-03-7569ff0296bd)$
student_02_c4beb0285b69@cloudshell:~ (qwiklabs-gcp-03-7569ff0296bd)$ kubectl logs example-job-zww22
3.1415926535897932384626433832795028841971693993751058209749445923078164062862089986280348253421170679821480865132823066470938446095505822317253594081284811174502841027019385211055596446229489549303819644288109756659334461284756482337867831652712019091456485669234603486104543266482133936072602491412737245870066063155881748815209209628292540917153643678925903600113305305488204665213841469519415116094330572703657595919530921861173819326117931051185480744623799627495673518857527248912279381830119491298336733624406566430860213949463952247371907021798609437027705392171762931767523846748184676694051320005681271452635608277857713427577896091736371787214684409012249534301465495853710507922796892589235420199561121290219608640344181598136297747713099605187072113499999983729780499510597317328160963185950244594553469083026425223082533446850352619311881710100031378387528865875332083814206171776691473035982534904287554687311595628638823537875937519577818577805321712268066130019278766111959092164201989380952572010654858632788659361533818279682303019520353018529689957736225994138912497217752834791315155748572424541506959508295331168617278558890750983817546374649393192550604009277016711390098488240128583616035637076601047101819429555961989467678374494482553797747268471040475346462080466842590694912933136770289891521047521620569660240580381501935112533824300355876402474964732639141992726042699227967823547816360093417216412199245863150302861829745557067498385054945885869269956909272107975093029553211653449872027559602364806654991198818347977535663698074265425278625518184175746728909777727938000816470600161452491921732172147723501414419735685481613611573525521334757418494684385233239073941433345477624168625189835694855620992192221842725502542568876717904946016534668049886272327917860857843838279679766814541009538837863609506800642251252051173929848960841284886269456042419652850222106611863067442786220391949450471237137869609563643719172874677646575739624138908658326459958133904780275901
student_02_c4beb0285b69@cloudshell:~ (qwiklabs-gcp-03-7569ff0296bd)$
The output will show that the job wrote the first two thousand digits of pi to the Pod log.
student_02_c4beb0285b69@cloudshell:~ (qwiklabs-gcp-03-7569ff0296bd)$ kubectl delete job example-job
job.batch "example-job" deleted
student_02_c4beb0285b69@cloudshell:~ (qwiklabs-gcp-03-7569ff0296bd)$
If you try to query the logs again the command will fail as the Pod can no longer be found.
student_02_c4beb0285b69@cloudshell:~ (qwiklabs-gcp-03-7569ff0296bd)$ kubectl get pods
No resources found in default namespace.
student_02_c4beb0285b69@cloudshell:~ (qwiklabs-gcp-03-7569ff0296bd)$ kubectl logs example-job-zww22
Error from server (NotFound): pods "example-job-zww22" not found
student_02_c4beb0285b69@cloudshell:~ (qwiklabs-gcp-03-7569ff0296bd)$
Define and deploy a CronJob manifest
You can create CronJobs to perform finite, time-related tasks that run once or repeatedly at a time that you specify.
In this task, you create and run a CronJob, and then you clean up and delete the Job.
This CronJob deploys a new container every minute that prints the time, date and “Hello, World!”.
- Create and open a file called
example-cronjob.yaml
student_02_c4beb0285b69@cloudshell:~ (qwiklabs-gcp-03-7569ff0296bd)$ cat example-cronjob.yaml
apiVersion: batch/v1
kind: CronJob
metadata:
name: hello
spec:
schedule: "*/1 * * * *"
jobTemplate:
spec:
template:
spec:
containers:
- name: hello
image: busybox
args:
- /bin/sh
- -c
- date; echo "Hello, World!"
restartPolicy: OnFailure
student_02_c4beb0285b69@cloudshell:~ (qwiklabs-gcp-03-7569ff0296bd)$
CronJobs use the required schedule field, which accepts a time in the Unix standard crontab format.
All CronJob times are in UTC:
- The first value indicates the minute (between 0 and 59).
- The second value indicates the hour (between 0 and 23).
- The third value indicates the day of the month (between 1 and 31).
- The fourth value indicates the month (between 1 and 12).
- The fifth value indicates the day of the week (between 0 and 6).
The schedule field also accepts * and ? as wildcard values. Combining / with ranges specifies that the task should repeat at a regular interval. In the example, */1 * * * * indicates that the task should repeat every minute of every day of every month.
student_02_c4beb0285b69@cloudshell:~ (qwiklabs-gcp-03-7569ff0296bd)$ kubectl apply -f example-cronjob.yaml
Warning: autopilot-default-resources-mutator:Autopilot updated CronJob default/hello: defaulted unspecified 'cpu' resource for containers [hello] (see http://g.co/gke/autopilot-defaults).
cronjob.batch/hello created
student_02_c4beb0285b69@cloudshell:~ (qwiklabs-gcp-03-7569ff0296bd)$
student_02_c4beb0285b69@cloudshell:~ (qwiklabs-gcp-03-7569ff0296bd)$ kubectl get jobs
NAME COMPLETIONS DURATION AGE
hello-28633048 1/1 5s 22s
student_02_c4beb0285b69@cloudshell:~ (qwiklabs-gcp-03-7569ff0296bd)$
student_02_c4beb0285b69@cloudshell:~ (qwiklabs-gcp-03-7569ff0296bd)$ kubectl describe job hello-28633048
Name: hello-28633048
Namespace: default
Selector: batch.kubernetes.io/controller-uid=adcad3d9-a3d0-4656-8642-4d1ad84a2068
Labels: batch.kubernetes.io/controller-uid=adcad3d9-a3d0-4656-8642-4d1ad84a2068
batch.kubernetes.io/job-name=hello-28633048
controller-uid=adcad3d9-a3d0-4656-8642-4d1ad84a2068
job-name=hello-28633048
Annotations: batch.kubernetes.io/cronjob-scheduled-timestamp: 2024-06-10T01:28:00Z
Controlled By: CronJob/hello
Parallelism: 1
Completions: 1
Completion Mode: NonIndexed
Start Time: Mon, 10 Jun 2024 01:28:00 +0000
Completed At: Mon, 10 Jun 2024 01:28:05 +0000
Duration: 5s
Pods Statuses: 0 Active (0 Ready) / 1 Succeeded / 0 Failed
Pod Template:
Labels: batch.kubernetes.io/controller-uid=adcad3d9-a3d0-4656-8642-4d1ad84a2068
batch.kubernetes.io/job-name=hello-28633048
controller-uid=adcad3d9-a3d0-4656-8642-4d1ad84a2068
job-name=hello-28633048
Containers:
hello:
Image: busybox
Port: <none>
Host Port: <none>
Args:
/bin/sh
-c
date; echo "Hello, World!"
Limits:
cpu: 500m
ephemeral-storage: 1Gi
memory: 2Gi
Requests:
cpu: 500m
ephemeral-storage: 1Gi
memory: 2Gi
Environment: <none>
Mounts: <none>
Volumes: <none>
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal SuccessfulCreate 59s job-controller Created pod: hello-28633048-ck7dd
Normal Completed 53s job-controller Job completed
student_02_c4beb0285b69@cloudshell:~ (qwiklabs-gcp-03-7569ff0296bd)$
student_02_c4beb0285b69@cloudshell:~ (qwiklabs-gcp-03-7569ff0296bd)$ kubectl get pods
NAME READY STATUS RESTARTS AGE
hello-28633048-ck7dd 0/1 Completed 0 117s
hello-28633049-z7kvx 0/1 Completed 0 57s
student_02_c4beb0285b69@cloudshell:~ (qwiklabs-gcp-03-7569ff0296bd)$
student_02_c4beb0285b69@cloudshell:~ (qwiklabs-gcp-03-7569ff0296bd)$ kubectl logs hello-28633048-ck7dd
Mon Jun 10 01:28:03 UTC 2024
Hello, World!
student_02_c4beb0285b69@cloudshell:~ (qwiklabs-gcp-03-7569ff0296bd)$ kubectl logs hello-28633049-z7kvx
Mon Jun 10 01:29:02 UTC 2024
Hello, World!
student_02_c4beb0285b69@cloudshell:~ (qwiklabs-gcp-03-7569ff0296bd)$
student_02_c4beb0285b69@cloudshell:~ (qwiklabs-gcp-03-7569ff0296bd)$ kubectl get jobs
NAME COMPLETIONS DURATION AGE
hello-28633048 1/1 5s 3m4s
hello-28633049 1/1 5s 2m4s
hello-28633050 1/1 4s 64s
hello-28633051 0/1 4s 4s
student_02_c4beb0285b69@cloudshell:~ (qwiklabs-gcp-03-7569ff0296bd)$ kubectl get pods
NAME READY STATUS RESTARTS AGE
hello-28633049-z7kvx 0/1 Completed 0 2m10s
hello-28633050-ngwhf 0/1 Completed 0 70s
hello-28633051-nmjzw 0/1 Completed 0 10s
student_02_c4beb0285b69@cloudshell:~ (qwiklabs-gcp-03-7569ff0296bd)$
By default Kubernetes sets the Job history limits so that only the last three successful and last failed jobs are retained so this list will only contain the most recent three of four jobs:
student_02_c4beb0285b69@cloudshell:~ (qwiklabs-gcp-03-7569ff0296bd)$ kubectl delete cronjob hello
cronjob.batch "hello" deleted
student_02_c4beb0285b69@cloudshell:~ (qwiklabs-gcp-03-7569ff0296bd)$
student_02_c4beb0285b69@cloudshell:~ (qwiklabs-gcp-03-7569ff0296bd)$ kubectl get jobs
No resources found in default namespace.
student_02_c4beb0285b69@cloudshell:~ (qwiklabs-gcp-03-7569ff0296bd)$ kubectl get pods
No resources found in default namespace.
student_02_c4beb0285b69@cloudshell:~ (qwiklabs-gcp-03-7569ff0296bd)$
All the Jobs were removed.
History
student_02_c4beb0285b69@cloudshell:~ (qwiklabs-gcp-03-7569ff0296bd)$ history
1 export my_region=us-east1
2 export my_cluster=autopilot-cluster-1
3 source <(kubectl completion bash)
4 gcloud container clusters get-credentials $my_cluster --region $my_region
5 kubectl get nodes
6 kubectl get pods
7 kubectl get nodes
8 kubectl get pods -A
9 nano example-job.yaml
10 cat example-job.yaml
11 kubectl apply -f example-job.yaml
12 kubectl describe job example-job
13 kubectl get pods
14 kubectl get nodes
15 kubectl get pods
16 kubectl get nodes
17 kubectl get pods
18 kubectl apply -f example-job.yaml
19 kubectl get pods
20 kubectl describe job example-job
21 kubectl get pods
22 kubectl describe job example-job
23 kubectl get jobs
24 kubectl logs example-job-zww22
25 kubectl delete job example-job
26 kubectl get pods
27 kubectl logs example-job-zww22
28 nano example-cronjob.yaml
29 cat example-cronjob.yaml
30 kubectl apply -f example-cronjob.yaml
31 kubectl get jobs
32 kubectl describe job hello-28633048
33 kubectl get pods
34 kubectl logs hello-28633048-ck7dd
35 kubectl logs hello-28633049-z7kvx
36 kubectl get jobs
37 kubectl get pods
38 kubectl delete cronjob hello
39 kubectl get jobs
40 kubectl get pods
41 history
student_02_c4beb0285b69@cloudshell:~ (qwiklabs-gcp-03-7569ff0296bd)$
